Reflection Asymmetric Powder Diffraction with Flat-Plate Sample using a Curved Position-Sensitive Detector (INEL CPS 120)

Abstract

The reflection flat-sample asymmetric geometry is an attractive set-up for powder diffraction measurements, as compared to either conventional Debye--Scherrer or symmetric Bragg-Brentano geometries. Combined with grazing-or fixed-incidence-angle X-rays, it is suitable for surface-structure or thin-film texture analysis. Furthermore, it allows curved position-sensitive detectors to be used for in situ experiments. In this paper, the major systematic error sources in connection with this geometry are reviewed. It is confirmed that experimental linearization of the curved position-sensitive detector and sample positioning have to be very carefully performed. Simple and automatable procedures are proposed. Then, it is shown that peak-location accuracy leads to satisfactory cell-parameter determination as checked by the use of a silicon international standard reference sample and that structure refinement by the Rietveld method can be performed in very good conditions, as observed with an NaBi2Sb3Oll compound.

Asymmetry of 1 nm XRD Reflection and Measurement of Illite Crystallinity

“…There have been five interpretations for asymmetry of a single XRD peak so far: (i) axial divergence [9][10][11]; (ii) layer structure [4]; (iii) secondary reflex [1,2]; (iv) sample transparency [10,12]; (v) mode of irradiation or geometric condition [12]. Among them (ii) and (iv) there are internal factors and the others are external factors.…”

Sol–gel processing of TeO2 thin films from citric acid stabilised tellurium isopropoxide precursor

“…The diffractometer consists in a Debye-Scherrer-like set-up, operating on flat samples, fitted with a forward quartz monochromator (Cu K ␣1 radiation) and a curve position sensitive detector (CPSD INEL, 120 • angular aperture) allowing the diffracted peaks to be simultaneously recorded. 16 This asymmetric geometry under controlled and fixed incidence is particularly suitable for surface characterization and thin film structure analysis. The incidence angle ω was fixed to about 3-7 • in order to favour the irradiated volume of the layer without impairing the resolution, i.e., without an excessive broadening of the X-ray diffraction line profile.…”

Phase separation in sol–gel derived ZrO2–SiO2 nanostructured materials

“…22 XRD experiments were carried out in a Debye-Scherrer geometry based diffractometer with a sealed tube operating at 37.5 kV/28 mA, a quartz monochromator (Cu K␣1 radiation) and equipped with a curved position sensitive detector (Inel CPS 120). 23 The mean crystallite size was determined using the integral breadth method. 24 Due to the X-ray diffraction line overlapping, the pattern simulations were done by Rietveld refinement 25 using the Fullprof package.…”